<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />
		<style>
			div{
				/*width:1200px;*/
				height:40px;
				
			}
			@media only screen and (min-width: 800px){
				div{
					background: red;
				}
			}
			@media only screen and (max-width: 799px) and (min-width:400px){
				div{
					background: green;
				}
			}
			@media only screen and (max-width: 399px){
				div{
					background: yellow;
				}
			}
		</style>
	</head>
	<body>
		<div></div>
	</body>
</html>
